Size Counts When It Comes to Sex

July 7, 2011 -- Being very thin or fat appears to increase the odds that a man will experience some kind of sexual difficulty, but the same may not be true for women, a new study shows.

The study, a survey of more than 5,500 adults in Denmark, finds some surprising and complicated associations between lifestyle factors and sexual health.

In men and women, for example, body size -- being either too thin or obese -- appears to be related to the risk of having sexual problems. For men, those extremes increase the risk. Women in those ranges, on the other hand, appear to have less sexual difficulty.

Similarly, men with very large waists, over 40 inches, had a 71% increased risk of having some kind of sexual trouble compared to men who had a waist size under 37 inches.

“What I found interesting was that the number of men who were underweight, or had low BMI [body mass index], had various elevated risks for sexual difficulties,” said Edward O. Laumann, professor of sociology and an expert in human sexuality at the University of Chicago. He was not involved in the current research.

He says having a large waist and a high BMI, which is also associated with health conditions like heart disease and diabetes, has long been known to be associated with an increased risk of sexual dysfunction in men.

Understanding why having a low BMI might also increase the risk is “less straightforward to figure out” and will require more research, he says.

Women, Weight, and Sex

Being underweight appeared to cut a woman’s chances of having sexual difficulties in half compared to a normal-weight, sexually active woman.

And obese women, with BMIs over 30, had 70% less chance of experiencing some kind of sexual dysfunction than their normal-weight counterparts.